Since its introduction a few years ago, the 6.8mm Special Purpose Cartridge (SPC/6.8x43mm) has been chambered for rifles and carbines by several manufacturers and ammunition is in production by several ammo makers, but there is another cartridge in the same class that bears examination, the 6.5 Grendel (6.5x38mm). Rifles in 6.5 Grendel are less common than the 6.8 for several reasons that are beyond the scope of this article. While possessing some similarities, the cartridges are very different and were designed for different purposes. The 6.8x43mm was recommended for adoption by US Special Forces some three years ago, but that has yet to occur for reasons that again are beyond the scope of our evaluation. Suffice to say that carbines chambered for the 6.8 cartridge haven’t been adopted by the military in any number and aren’t likely to be.
The 6.8 SPC was designed as a close quarters battle (CQB) to 400-meter cartridge that would deliver increased lethality compared to any 5.56x45mm (.223) cartridge. The 6.5 Grendel, on the other hand, was designed as a long-range cartridge that could be fired from an AR-type rifle. The 6.5 Grendel’s purpose was to provide an extreme range capability to AR-type rifles for hunting and competition. The fact that the 6.5 Grendel became a de facto competitor against the 6.8mm SPC derives from misunderstanding the purposes of the two cartridges. This, coupled with the 6.5’s superior long-range ballistics, has caused some in Special Forces to consider the 6.5 Grendel as a potential candidate to supplant if not replace the 6.8 SPC. On that, the jury is still out, but in an in-depth comparison in Infantry Magazine, Stan Crist noted that in terms of long-distance shooting, the 6.5 Grendel completely overshadows the 6.8 SPC. Even at closer ranges, the 6.5 has superior ballistics. The 6.5 Grendel is also more resistant to crosswinds due to its higher sectional density and superior ballistic coefficient.